An organic light emitting diode (OLED) is an organic thin-film electroluminescent device, which has the advantages of easily forming a flexible structure and a wide viewing angle, etc.; therefore, the display technology utilizing an organic light emitting diode has become an important display technology.
The full color display of an OLED generally comprises ways in which the R (red), G (green) and B (blue) sub-pixels emit light independently, or a white light OLED is combined with a color filter film, or the like. Therein, that the RGB sub-pixels emit light independently is a color mode currently most adopted, which utilizes organic light emitting materials in the sub-pixel units to emit light independently.
Nowadays, an organic light emitting material layer is generally formed by vacuum evaporation coating of the organic material. Therein, for an OLED in which the RGB sub-pixels emit light independently, since each RGB sub-pixel unit employs a different organic light emitting material, the organic light emitting layers of the RGB sub-pixel units need to be vapor deposited, respectively, and in this procedure, a metal mask plate is generally employed, such that its open areas are aligned with areas of the sub-pixels to vapor deposit light emitting materials of different colors in areas of different sub-pixels.
However, since the metal mask plate is relatively thin, generally only tens of microns thick, and is very easily deformed, which will in actual use inevitably result in looseness of the fitting of it to a substrate to be vapor deposited, such that a correct pattern can not be formed when the organic light emitting materials are vapor deposited.